Four Oirat

The Four Oirat was a confederation of Oirat tribes in Mongolia that existed from 1399 to 1634, namely the Choros, Torghut, Dorbet, and Khoid tribes. The Four Oirat was one of the successor kingdoms of the Mongol Empire, with former Yuan dynasty official Mongke-Temur founding the confederation after the end of the Mongols' rule over China. The Oirat rulers exercised control over the Northern Yuan after slaying its previous rulers and expanding their empire into eastern Mongolia, with Esen Taishi (r. 1438-1454) bringing the Oirats to the height of their power after driving back the monarchs of the Yarkent Khanate, and in 1449 the northern defenses of the Ming dynasty collapsed when the Zhengtong Emperor was captured by the Oirats. The might of the Oirats declined with Esen's overthrow and death in 1454, and the rise of Dayan Khan (r. 1479-1517) at the head of Northern Yuan led to the Oirats being pushed westward. By 1510, Dayan united all of the Mongol tribes, including the Oirats, but from 1552 to 1628 the Khalkhas of Inner Mongolia repeatedly raided the Oirats' lands. In 1620, the Khalkha Altan Khan scattered the Choros, and the majority of the fleeing Choros, Dorbets, and Khoids fled to form the Dzungar Khanate in 1634, bringing an end to the Four Oirat and starting the rise of the Dzungars.